Improvement in steam-valves



ZSheets-fiheetl. E. COPE & J. R. MAXWELL.

STEAM-VALVE.

Patented Dec.14,1875.

INVENTORS.

STEAM-VALVE.

Patented Dec.14,1875.

INVENTOBS.

VV'ITNESSESI.

N. PETERS. PNOTO-UTMOGRAPM nmE-D STATES PATENT ()rrron.

EZRA COPE AND JAMES It. MAXWELL, OF HAMILTON, OHIO.

IMPROVEMENT IN STEAM-VALVES.

Specification forming part of Letters Patent No. 170,939, dated December14, 1875; application filed September 17, 1874.

To all whom it may concern:

Be it known that we, EZRA COPE and JAMES R. MAXWELL, of the city ofHamilton, county of Butler and State of Ohio, have invented certain newand useful. Improvements in the Valves of Direct-Acting Engines; and wedeclare that the following is a full, clear, and exact descriptionthereof, reference being had to the accompanying drawings, which form apart of this specification.

The nature of our invention consists in improvements upon the valves ofdirect-acting engines, and the arrangement of ports and passages foractuating the same, whereby we secure simplicity of construction withthe most prompt and positive action.

In the drawings like parts are indicated by the same letters, and arrowsshow the direction of the moving parts and the flow of steam.

Figure 1, Sheet 1, is a longitudinal section through the cylinder,steam-chest, and valvegear. Fig. 2 is a transverse section through thesame parts. Fig. 3 is a plan of the valvegear. Figs. 4 and 5 are viewsof the supplementary slide-valve and its seat, showing the position ofthe ports. Fig. 6, Sheet 2, is a plan of the cylinder, showing thevalve'seat face and the position of the ports. Fig. 7 is a bottom viewof the main slide-valve, showing the position of its ports.

A is the main steam cylinder; B, the main piston and C, the steam-chest.D and D are small cylinders, in which two small tappetpistons of unequalareas, F F, work. These cylinders are cast and move with the mainslide-valve, they themselves constituting a piston moving in theauxiliary cylinders E E. D is a small auxiliary slide-valve, having itsseat upon the back of the main slide-valve. It is actuated by thetappet'pistons F F alternately. J J are lugs extending from thetappet-pistons F F, between and against which the lever L acts. Thelever L, shaft M, and handle N are an arrangement for moving the valvesby hand. The auxiliary cylinders E E are united by overlapping oneanother, as shown at t, Fig. 3, and are held firmly in position by thesteam'chest at the points I l, where the cylinders are rounded, so thatthey, with the Valve-gear, may always settle to their places.

or rebound of the tappet-pistons.

latter pressure serves to keep them from fluttering, and forces themback to their positions as soon as the steam is exhausted from thelarger area. The steam-passages A A and supplementary passages a a arearrangedas has been described in a previous patent. The passages a a, incombination with c and c, admit steam from the main cylinder to move thetappet-pistons F and F, and, in combination with the smallports p and10, they exhaust the steam from these pistons. These passages a and aare lengthened, and enter the cylinder a second time at b and b, soplaced that, when the main piston closes a. and a, b and b will be openand continue the exhaust from the tappet-pistons until the main pistonhas passed under and opened a and a, when b and b will be closed. Thisarrangement of ports prevents the steam remaining in the passage a or aafter they have been closed by the main piston, or any steam whichmayleak past the tappet pistons from moving these pistons, and soreversing the valves before the main piston has made its full stroke.The ports and passages m m, n and n, and cavity 0 are also intended toprevent the fluttering The passages n and n are alternately incommunication with the ports m m and the cavity 0. When in communicationwith m or m they slowly exhaust steam from the annular spacessurrounding the reduced portion of the tappetpistons. When communicatingwith cavity 0 they admit high steam from the chest to the same annularspaces. lhe passages g and g are brought into communication alternatelywith the passages f and f, and, through them, with the exhaust, by thecavity h in the auxiliary slide-valve D, and, with high steam in thechest, by the ports j and j in the same valve D. The ports j and j maybe dispensed with, the passages g and 9 being used wholly asexhaust-passages, and the small ports z and t" continually open to thechest, furnishing high steam to move the main slide-valve.

The operation is as follows: In the drawings hausted through n and m.

the main slide-valve is at the left of its travel, admitting steam tothe main cylinder through port A on the right, moving the main piston Bto the left. Upon passing under and opening pert a steam from behind itpasses through a and c to the left of the tappet-piston F. This beingthe larger area of the piston, the pressure of steam upon itoverbalances that which acts continuously upon the smaller area, whilethat in the annular space surrounding the smaller end of thistappet-piston is ex- The piston F, therefore, moves to the right. Inthis motion it comes in contact with'and carries on the auxiliaryslide-valve D. This valve D being moved to the right, the passages g andf are brought into communication through the cavity h, and passage 9 isbrought into communication with the port j in the valve D. Through theformer passages g and f" steam is exhausted from the auxiliary cylinderE, while through the latter, 9 and j, high steam is supplied to theauxiliary cylinder E. The cylinders D D and main slide-valve thereforemove to the right. In this motion the passage 0 is brought intocommunication with the port 10, exhausting steam from the left of thetappet piston F. At'the same time passage n and cavity 0 communicate,and high steam passes to the annular space around F. This piston F isthen thrown back to its former position. The passage 0 is brought intocommunication with a, ready for the reception of steam, when the mainpiston shall have passed under and opened a on its return stroke. Thepassage f is carried over the port f, and the main slide-valve cushionedupon the remaining steam. The main slide-valve having been reversed, aswe have seen, steam is admitted to the main cylinder through the passageA on the left, and exhausted through A and B on the right, so reversingthe stroke of the main piston B. When the piston B, on its returnstroke, has passed under and opened a, steam passes to the tappet-pistonF, moving it to the left, and with it the supplementary slide-valve D",and the same operations are repeated in a reverse order, and so oncontinuously while steam is supplied.

Having fully described the operation and construction of our invention,what we claim, and desire to secure by Letters Patent, is-

1. The tappet-pistons F F, constructed of two unequal areas, with aconstant pressure of steam upon the smaller area, operated independentlyof each other, in combination with the cylinders D D and the ports andpassages a a b b c c m m n n and the cavity 0, arranged to operatetogether in the manner described.

2. The auxiliary cylinders E E, with their outer ends closed, and innerends united by an overlapping joint, it, supported by the mainslide-valve and cylinders D D, and held'iu place at the points I l bylugs cast within the steam-chest, substantially as described.

3. The combination of the main slide-valve and cylinders D D, theauxiliary cylinders E E, the auxiliary slide-valve D, the tappetpistonsF F, and the ports and passages a a, cc, 9 g, jj, ff f, and h 72/,arranged and operated substantially as described.

EZRA COPE.

- JAS. R. MAXWELL.

Witnesses:

SAML. W. GREENE, Rom. MCKINNEY.

